The present invention relates to a remote copy technique for duplicating data between storage systems without intervention of a host computer.
As a technique of avoiding data loss in a storage system in case of a disaster or the like, remote copying is employed to duplicate data to another storage system located in a remote place. Here, it is assumed that a storage system includes a storage device such as a disk or the like and a storage controller connected to the storage device for controlling data input and output to and from the storage device. The remote copying is a technique in which a storage system in a local site (hereinafter, also referred to as a primary storage system) transfers data in the primary storage system to another storage system (hereinafter, also referred to as a secondary storage system) located in a remote place (hereinafter, also referred to as a remote site), and the secondary storage system stores the data received from the primary storage system into the storage device of the secondary storage system. With respect to remote copying, there is disclosed a technique of duplicating data between different storage controllers without intervention of a host computer (hereinafter, referred to as a host) (See Patent Document 1).
Further, data migration is a technique of migrating data stored in an old storage system to a new storage system at the time of replacement of the old storage system with the new storage system. With respect to data migration, there are disclosed techniques in which data of a storage system is migrated to another storage system without stopping the job executed in a host computer so that the job may not be affected by the migration (See Patent Documents 2 and 3).
Further, there is disclosed a technique in which data migration is performed between storage systems while suppressing effect on remote copying to the minimum (See Patent Document 4). This technique can keep the remote copy function operable in the course of data migration. Further, completeness of data can be maintained, since update data is stored in both the old and new storage systems in the course of data migration.
Patent Document 1 is Japanese Non-examined Patent Laid-open No. 11-85408;
Patent Document 2 is Japanese Non-examined Patent Laid-open No. 11-184641;
Patent Document 3 is Japanese Non-examined Patent Laid-open No. 2003-108315; and
Patent Document 4 is Japanese Non-examined Patent Laid-open No. 2003-85018.